以前好像有朋友問過這個問題？不妨看看下面文章： ============================= http://www.custom-sounds.com/18volts.htm 18Volts I first read about this in 1979 in The Guitar Book by Tom Wheeler, page 280 1978 edition. " If your fuzz unit isn't raspy enough, you can increase both its volume and distortion capabilities with the addition of an extra battery. However, you are risking possible damage to the transistors, so experiment with caution." The Fuzz- , Distortion-, Overdrive effects are often set around a specific voltage range. A classic way of obtaining these effects is to take a well biased circuit and lower its supply voltage until you get the desired effect. An example of such a circuit is the OP-amp. Many popular effects rely on the blend of distortion products of an OP-amp in conjunction with limiting in some form. A great many OP's are designed to work at a supply voltage of no less than 9 Volts or performance is compromised - meaning high levels of distortion can be expected from the OP as internal bias supplies may be offset. The op-amps were not originally designed to be used on overdrive or other pedals and the optimum voltage for them is often higher than 9 Volts. In an OP-amp based circuit with clipping diodes, higher voltage means less influence of the OP, it works more linear, up to a point when something fuses - often a filtercap. Maximum distortion-less gain in a circuit powered by 18Volts, driven by an ordinary humbucker is however 35 dB as opposed to 18 dB in the same system powered by 9 Volts. In a discrete design ( only transistors or tubes ) the working point of internal stages is set within a limited span. Raising or lowering supply voltage beyond the limits of the span directly affects linearity of the circuit, and the exact overtones produced. Discrete designs are usually less tolerant to supply voltages outside the design limits - very unpleasant sounds may be the result when using OP-amp based pedals with non-standard voltage. Most pedals designed for 9 Volt supplies have components rated safely above 9Volt, but rarely safely above 18Volts. Electrolytic capacitors used in powersupply filtering, are made with specific voltage ratings e.g. 10V, 16V, 25V, 35V , 50V. In 9Volt powered effects 16V rated components are often used because they are physically smaller than say 25V types. This may be of significance if space is limited. Applying higher voltage than rated to such a capacitor will seriously shorten its life and may result in an explosion. One of the design criterions of BJF- pedals where that it should be feasible to power them from a 9 Volt battery at good economy. This was achieved by low current draw or ability to work from low voltage. Extensive tests were made to set acceptable voltage range to each pedal. Performance has been optimized for a supply ranging from 7,5V to 12V, taking into account that a fresh battery may leave 10,5 Volts, but would be considered empty at 7,5Volts. It would be likely that a pedal sometimes would be powered from a 12V supply, since many pedalboard supplies can deliver that (like Voodoo Lab Pedalpower-2). You would get more output dynamics and overally cleaner sound. This however does not work if supply is increased further as bias systems may be overridden or even blown. Had the standard been 18 Volts instead of 9 Volts the pedals would have been made differently because a designer would try to make the best out of the voltage range given and it is actually much harder to make things work at 9 V than at 18V. I remember having a hard time with pedals requiring 18V because batteries were (are) expensive. There were solutions like electronically fabricate a negative 5V supply from a 9Volt battery giving a total of 14 V but that would typically be 1V low from lowest supply acceptable with these 18V effects, that were very often regulated internally for 12V to keep bias steady. Bjorn "Mad Professor" Juhl
18Vdc很簡單：一、去買18Vdc regulated的ac/dc adaptor。二、用兩個9V的電池串聯（即電池甲的正極接電池乙的負極，然後剩下未接的兩極間就有18V的電位差。你再買一個或三個電池夾就可以改了）。三、同理，兩顆9V的ac/dc adaptor串聯，或你有Voodoo Lab Pedal Power的話，兩個output串聯也有18V。但值得擔心的反倒是你的FD-2是否真能在18V上工作？單顆效果器（特別是boutique一脈）不同時期製作，用的零件不見得會是一樣的。請參考Jeff上面的文章，像是 電容器耐壓等可以自己先檢查一下（電容器上面會有標示）。